Fungicidal sulfur-containing phenyl esters and mixtures thereof

ABSTRACT

A broad spectrum sulfur-containing fungicide having the formula ##STR1## wherein X is sulfide, disulfide, sulfinyl, sulfonyl or sulfonate; m has a value of from 0 to 2; halo is fluorine, chlorine or bromine; and R is a radical having not more than 4 carbon atoms selected from the group consisting of alkenyl, haloalkenyl and haloalkyl; and the method of applying said esters to plants for control of fungi infestation.

This invention relates to fungicides, and more particularly to broadspectrum biocides as eradicants and protectants against infestation byplant pathogens.

The effective mycological inhibition evidenced by differentiatedchemical species is a complex function of a number of variablesincluding specific activity, resistance to weathering, the type of planttreated, the degree of infestation and varying levels of phytotoxicity.Ecological considerations have barred the use of many effectivefungicides because of their persistent residues and toxicity to humansby prolonged ingestation of food crops. To be commercially acceptablecurrent fungicides must leave no toxic residue, they must be easilyhandled, operate consistently within a spray schedule and be economicalto prepare. The foregoing requirements limit the selection of totallyacceptable, effective fungicidal agents to a relatively small group ofcompounds. While many of the available materials comprise complexmolecules of specific functionality, most are difficult or expensive toprepare and many of these materials, while effective against onefungicidal species, e.g. rusts, are not effective against other species,e.g. mildew or anthracnose. Such highly specialized fungicidesnecessitate the use of several sprays for controlling multifungicidalinfestation; thus, increasing the amount of residue remaining on theplant or in the soil.

Accordingly, it is an object of the present invention to provide aneffective broad spectrum fungicide for the control of mildews, rusts andanthracnose, suitable for application to plants and particularlysuitable for food crops since, under normal conditions, these compoundsleave no toxic residue.

It is another object of the present invention to provide effectivemycological agents which are economical to prepare and convenient touse.

In accordance with the present invention, there is provided a broadspectrum, fungicidally effective compound having the formula ##STR2##wherein X is sulfide (--S--), disulfide (--S--S--), sulfinyl (═SO),sulfonyl (═SO₂) or sulfonate ##STR3## m has a value of from 0 to 2; halois fluorine, chlorine or bromine and R is a radical having from 1 to 4carbon atoms selected from the group consisting of alkenyl, haloalkenyland haloalkyl; the acryloyl, chloroalkyl and bromoalkyl derivativesbeing preferred. The alkenyl and haloalkyl groups of the presentcompounds may be of a linear, branched or cyclic type. Alkenyl isintended to include multi olefinic unsaturation; however,mono-unsaturated and halosubstituted radicals having the functionalmoiety at their terminal carbon atoms are preferred. It is also to beunderstood that mixtures of the above sulfur containing ester compoundsmay be employed in the operation of the present invention.

In general the ester compounds of the present invention are preparedaccording to the processes described in British Pat. No. 740,101, Nov.9, 1955; Vestn. Akad. Nauk Kaz. SSR 1971, 27(9) 53-9 by M. Kurmanalievet al. and Makromol Chem. 1970, 136, 161-72 and 1969, 129, 125-36 by H.Kaemmerer et al. which publications are incorporated herein byreference. Specifically, the ester substituted compounds are easily andeconomically prepared by reacting an unsaturated acyl halide optionallysubstituted with halogen or a halocarboxylic acid halide with adiphenolic sulfide, sulfone, sulfine or sulfite in the presence of abase such as for example triethylamine, sodium carbonate, pyridine, etc.and a solvent selected from the group consisting of methylene chloride,toluene, xylene, benzene or a liquid aliphatic hydrocarbon such asheptane, octane, cyclohexane, or any other conventional inert organicsolvent. The reaction can be carried out at a temperature of from about-25° C. to about 20° C. under atmospheric pressure for a period of fromabout 0.5 to about 2 hours. The organic layer is washed with water toextract the halide salt by-product, dried over a desiccant, e.g.magnesium sulfate, filtered to remove desiccant and vacuum distilled toremove solvent.

The product is recovered in a high yield and purity, for example, thereis obtained at least 80% conversion of which about 90% is the desiredproduct.

The corresponding haloalkyl esters are prepared by reacting thecorresponding halogenated carboxylic acid halide with an above defineddiphenol at a temperature of from about -25° C. to about 20° C. underatmospheric pressure. Other methods of preparation will become apparentto those skilled in the art from the above discussion of desirablecompounds and the above described reaction conditions. Examples ofsuitable halogenated carboxylic acid halides include the chlorides orbromides of chloroacetic; 3-chloropropionic; dichloroacetic;4-bromobutyric; 2,3-dichloropropionic; 3-trifluoromethyl propionic;2,3,4-trichlorobutyric acids and other mono- and poly-halogenatedcarboxylic acid halides.

The phenolic reactants which can be used in the process for preparingthe compounds of the present invention are those having the formula##STR4## wherein X is bivalent and is selected from the group of##STR5## halo is as defined above and m' has a value of 1 to 2 andmixtures of said phenolic reactants.

Examples of the above phenolic reactants includebis(4-hydroxy-2-chlorophenyl)sulfide;bis(4-hydroxy-2-bromophenyl)sulfide;bis(4-hydroxy-2-fluorophenyl)sulfide;bis(4-hydroxy-2,6-dichlorophenyl)sulfide; bis(2-hydroxyphenyl)sulfide;bis(5-hydroxy-2-chlorophenyl)sulfide;bis(4-hydroxy-2,5-difluorophenyl)sulfide;bis(4-hydroxy-2,6-dibromophenyl)sulfide; bis(4-hydroxyphenyl)sulfide;bis(3-hydroxyphenyl)sulfide; and the corresponding disulfides,sulfinyls, sulfonyls and sulfonates of the above sulfides and isomersand haloanalogs thereof.

The unsaturated acyl halide of the above reaction is defined as havingthe structure: ##STR6## wherein R' is hydrogen, chlorine or bromine; R"is hydrogen or methyl; n has a value of 0 to 2 and halo is chlorine orbromine. Of this group acryloyl chloride and methacryloyl chloride aremost preferred.

Representative of the products of this invention are included:

bis(4-acryloxy-2-chlorophenyl)sulfide;

bis(4-acryloxy-3-fluorophenyl)sulfide;

bis(4-acryloxy-2-bromophenyl)sulfide;

bis(4-acryloxy-2,6-dichlorophenyl)sulfide;

bis(4-acryloxy-2,5-dibromophenyl)sulfide;

bis(4-acryloxy-2,6-difluorophenyl)sulfide;

bis(4-acryloxy-phenyl)sulfide;

bis(4-methacryloxy-3-chlorophenyl)sulfide;

bis(4-methacryloxy-2-bromophenyl)sulfide;

bis(4-methacryloxy-2-fluorophenyl)sulfide;

bis(4-methacryloxy-2,6-dichlorophenyl)sulfide;

bis(4-methacryloxy-2,6-dibromophenyl)sulfide;

bis(4-methacryloxy-phenyl)sulfide;

bis(4-α-chloroacetoxy-3-fluorophenyl)sulfide;

bis(4-α-chloroacetoxy-2-bromophenyl)sulfide;

bis(4-α-chloroacetoxy-2-chlorophenyl)sulfide;

bis(4-α-chloroacetoxy-2,6-dichlorophenyl)sulfide;

bis(4-α-chloroacetoxy-2,6-dibromophenyl)sulfide;

bis(4-α-chloroacetoxy-phenyl)sulfide;

bis(4-α,β-dichloropropanoyloxy-3-chlorophenyl)sulfide;

bis(4-α,β-dichloropropanoyloxy-2,6-dichlorophenyl)sulfide;

bis(4-α,β-dichloropropanoyloxy-phenyl)sulfide;

bis(4-β-bromoacryloxy-2-bromophenyl)sulfide;

bis(4-β-bromoacryloxy-2,6-dibromophenyl)sulfide;

bis(4-β-bromoacryloxy-phenyl)sulfide;

bis 4,4'-(3,4-dichlorobutanoyloxy-2-chlorophenyl)sulfide;

bis 4,4'-(3,4-dichlorobutanoyloxy-2,6-dichlorophenyl)sulfide;

bis 4,4'-(3,4-dichlorobutanoyloxy-phenyl)sulfide;

and the corresponding disulfides, sulfinyls, sulfonyls, and sulfonatesof the above sulfides and isomers and haloanalogs thereof.

The esters of the present invention effect inhibition of widely variantplant pathogens and may be generally used in the control of infestationson many species of plants by application prior to infestation as aprotectant or after infestation to retard established growth. Althoughthe present products may be applied in full strength, directly to aplant or plant part, for economy and better distribution, the product ispreferably applied in diluted form as a liquid solution or dispersion oras a particulate solid or a dust. Suitable liquid carriers for thepresent products include water and organic solvents such as isopropanol,ethylene glycol, acetone, benzene, toluene, polyethylene glycol,polypropylene glycol, and other conventional inert carriers. Exemplaryof the solid carriers suitably employed with the present products aretalc, bentonite, diatomaceous earth clays, and the like.

The concentration of the active fungicide varies with the species ofplant treated, the mycological species sought to be controlled, climaticconditions and the particular fungicide employed; however, the presentproducts are usually applied in a concentration of between about 5 andabout 300 parts per million, preferably between about 20 and about 200parts per million, applied to provide coverage of from about 1 to about30 lbs. per acre, preferably about 3 to about 25 lbs. per acre. Incertain cases involving a persistent or heavy fungicidal infestation, itmay be desirable to employ solutions up to 500 ppm of the presentfungicides.

The fungicidal compositions of the present invention may also be appliedto or compounded in or with other substrates susceptible to fungalinfestation including wood, paper, leather textiles etc.; however theirpreferred utility is expressed in the field of agriculture, andparticularly in the control of plant pathogens as by foliar applicationas a liquid spray or dust either to growing crops or processedagricultural products, e.g. picked fruit or vegetables. The presentproducts may also find utility as bacteriocides in household orcommercial washing or cleansing solutions.

The fungicidal products can be formulated and applied with carrier orthey may be incorporated in available formulations containing otheragriculturally active agents such as plant growth regulators,insecticides, fertilizers or herbicides, as are presently marketed. Inall cases, the fungicidal compositions of this invention are used infungicidally effective amounts in the desired formulation. Liquidcompositions containing the present fungicides can be applied to plantsby spraying to drench, by misting or by immersing picked fruit orvegetables in a fungicidal solution. Also wrappings for fruits andvegetables can be impregnated with the present fungicide/carriercomposition to prevent rot or decay during shipment and distribution.

If desired, the present fungicidal compositions may include any of theconventional adjuvants such as surfactants, thickening agents, orsticking agents.

Having generally described the present invention, reference is now hadto the accompanying examples which illustrate preferred embodiments butwhich are not to be construed as limiting the scope of the invention asset forth in the foregoing description and in the appended claims. Allamounts and proportions recited in the following examples are by weightunless otherwise indicated.

EXAMPLE 1

Powdery mildew. The bean powdery mildew is an obligately parasiticfungus that must be transferred directly from infected plants to healthyplants in a relatively dry environment. In the present tests, healthyyoung bean plants with fully expanded primary leaves in 21/2" pots wereplaced for 2 days on a greenhouse bench between two rows of infectedplants covered with a mass of white, powdery conidia, and exposed to ashower of conidia.

Plants with incipient infection were atomized while rotating on aturntable with an aqueous solution of 250 ppm of test material shown inTable I and the soil was drenched with 21 ml of a 520 ppm solution (at arate equivalent to 25 lb/acre). The treated plants were then returned tothe greenhouse bench near infected plants. After 7 days observationswere made on the eradication of established infection present on theprimary leaves at the time of spraying. The plants were reexamined 7days later for infection on new growth as well as on the primary leavesto determine residual and systemic effects on the fungus. On bothoccasions the leaves are rated as % control of mildew.

                                      TABLE I                                     __________________________________________________________________________                              % Control of Infestation                                                      Arrested                                                                            Eradicated                                    Test Compound    Chemical Name                                                                          (14 Days)                                                                           (7 Days)                                      __________________________________________________________________________     ##STR7##        4,4'-diacryloxy- diphenyl sulfide                                                      100   40                                             ##STR8##        4,4'-diacryloxy- diphenyl sulfone                                                       70   40                                            __________________________________________________________________________

EXAMPLE 2

Bean rust (Uromyces phaseoli) is representative of a large number ofobligate parasites whose prolificacy in generating new parasitic raceshas frequently frustrated efforts to control them by breeding fordisease resistance. The present tests were made with separate aqueoussolutions each containing 260 ppm the compounds shown in Table II onPinto beans grown in 2.5 inch pots for 9 to 12 days by a combination offoliage spray and systemic protection from soil applications. In thetest 21 ml of a 520 ppm formulation (equivalent to 25 lb/acre) waspoured on the surface of the soil. At the same time the foliage wassprayed with 100 ml of the aqueous solutions containing 260 ppm of thecompounds shown in Table I while plants were rotating on a turntable.After the spray deposit had dried, the plants were atomized with asuspension of uredospores (summer spore stage) and placed in a moistchamber at 70° F. for 24 hours. After 7 to 9 days the severity ofpustule formation was rated in % control, as compared to untreatedcontrols. The results are reported in following Table II.

                                      TABLE II                                    __________________________________________________________________________                                 % Control of                                     Test Compound    Chemical Name                                                                             Rust Infestation                                 __________________________________________________________________________     ##STR9##        4,4'-di-3-chloropropan- oyloxy diphenyl                                                   100 one                                           ##STR10##       4,4'-di-3-chloropropan- oyloxy diphenyl                                                   100 ide                                           ##STR11##       4,4'-diacryloxy diphen- yl sulfide                                                        100                                               ##STR12##       4,4'-diacryloxy-2,2'- dichlorophenyl sulfide                                              90                                                ##STR13##       4,4'-diacryloxy-2,2' ,6,6'- tetrabromophenyl                                              90lfone                                           ##STR14##       4,4'-diacryloxy diphen- yl sulfone                                                        90                                                ##STR15##       4,4'-diacryloxy diphen- yl sulfoxide                                                      100                                               ##STR16##       4,4'-di-2-butenyloxy diphenyl sulfide                                                     90                                                ##STR17##       4,4'di-2-butenyloxy diphenyl sulfoxide                                                    100                                               ##STR18##       4,4'-di-2-butenyloxy diphenyl sulfone                                                     90                                                ##STR19##       4,4'-dichloroacetoxy diphenyl sulfide                                                     50                                               __________________________________________________________________________

The above compounds did not exhibit systemic activity; hence; foliarapplication is recommended.

EXAMPLE 3

Cucumber anthracnose (Colletotrichum lagenarium) is a representative ofleaf blights caused by the Fungi Imperfecti. Tests were made on cucumberplants grown in 2.5 inch pots for 9-12 days by a combination of foliagespray. In the test, the foliage was sprayed with 100 ml of a 250 ppmaqueous formulation of the compounds reported in Table III as describedbelow. After the spray deposit had dried, the treated plants wereinoculated with a suspension of anthracnose conidia in water and placedin a moist chamber at 24° C. for 24 hours. Four days after inoculation,the number of lesions were counted, and % control reported.

                  TABLE III                                                       ______________________________________                                                           % Control of                                               Test Compound      Anthracnose Infestation                                    ______________________________________                                         ##STR20##         100                                                         ##STR21##         100                                                         ##STR22##         100                                                         ##STR23##         100                                                         ##STR24##         100                                                         ##STR25##          10                                                         ##STR26##         100                                                        ______________________________________                                    

When 4,4'-diacryloxy-2,2'-dichlorophenyl- or4,4'-diacryloxy-2,2'-dichlorophenyl-sulfones are substituted in thisexample, at least 70% control of anthracnose is obtained.

EXAMPLE 4

The general procedures described the above examples 2 and 3 wererepeated for test compounds at varying concentrations reported in TableIV. Control of the rust and anthracnose, at various fungicidalconcentration levels are reported in following Table IV.

                                      TABLE IV                                    __________________________________________________________________________                          % Control of Pathogen                                   Test Compound    Pathogen                                                                           130 ppm                                                                            65 ppm                                                                             33 ppm                                                                             16 ppm                                                                             8 ppm                               __________________________________________________________________________     ##STR27##       R* A*                                                                              90 80                                                                              70 80                                                                              50 40                                                                              -- --                                                                              -- --                                ##STR28##       R A  70 0 30 10                                                                              20 50                                                                              -- --                                                                              -- --                                ##STR29##       R A  100 100                                                                            90 100                                                                             100 100                                                                            70 70                                                                              40 30                                ##STR30##       R A  90 100                                                                             90 90                                                                              90 50                                                                              70 --                                                                              40 --                                ##STR31##       R A  90 50                                                                              70 20                                                                              30 0 -- --                                                                              -- --                                ##STR32##       R A  -- 100                                                                             -- --                                                                              -- --                                                                              -- --                                                                              -- --                               __________________________________________________________________________     *R = rust; A = anthracnose                                               

Of the above compounds, the sulfide and the sulfone of diacryloxyphenyl,both at a concentration level of 65 ppm, additionally provided about 50%control of powdery mildew on bean plants.

As shown in the above tables, the most preferred concentration levels ofthe present fungicidal compounds fall within the range of between about30 and about 300 ppm. Other compounds, included within the scope of thepresent invention may require higher concentrations to achieve maximumeffectiveness, e.g., concentrations of up to about 500 ppm. The presentcompounds are advantageously used on edible crops since they leave notoxic residue and have no systemic effect beyond 2 weeks followingapplication. These properties make the present fungicidal compoundsideal for treatment of picked fruit and vegetables to prevent spoilagein shipment and storage.

It is to be understood that many variations and modifications of theabove examples will become apparent to those skilled in the art and areconsidered to be in the scope of the invention. For example, the presentfungicides may be incorporated into solid carriers such as clay, talc,pumice, or bentonite to provide compositions which may be applied eitherto infested areas on the plant or to areas which may be subjected toinfestation. They may also be dissolved in liquified gases such asmethyl chloride and applied as aerosol sprays containing the solution.Also, any of the corresponding mono- or di-hydroxy phenyl sulfides,sulfones, sulfines or sulfites can be substituted in the above examplesto provide similar fungicidal control.

I claim:
 1. The method of inhibiting growth of fungi which comprisesexposing said fungi to a growth inhibiting quantity of a compound havingthe formula ##STR33## wherein X is --S--, --SS--, --SO--, --SO₂ -- or--SO₃ -- m has a value of from 0 to 2; halo is fluorine, chlorine orbromine and R is a radical having not more than 4 carbon atoms selectedfrom the group consisting of alkenyl, haloalkenyl and haloalkyl; andmixtures of said compounds.
 2. The method of claim 1 wherein saidcompound is applied to a plant in an amount sufficient to prevent orcontrol fungus infestation.
 3. The method of claim 2 wherein RCO₂ -- ofthe compound is an acrylate radical.
 4. The method of claim 2 whereinRCO₂ -- of the compound is a methacrylate radical.
 5. The method ofclaim 2 wherein R of the compound is a haloethyl group and halo ischlorine or bromine.
 6. The method of claim 3 wherein the compound is asulfone.
 7. The method of claim 3 wherein the compound is a sulfide. 8.The method of claim 2 wherein the compound is employed with an aqueouscarrier in a concentration of between about 30 and about 500 ppm.
 9. Themethod of claim 8 wherein the fungus is plant rust.
 10. The method ofclaim 8 wherein the fungus is anthracnose.